According to The National Center for Home Food
Preservation (a land-grant university consortium sponsored by the USDA, and
considered to be the leading authorities on food safety science and food
preservation research) (and I am quoting them here):

“Home canning
is
not
recommended for pumpkin butter or any mashed or pureed pumpkin or
winter squash, but we do have directions for canning cubed pumpkin.
Pumpkin puree can be frozen or made into a spicy pumpkin leather…

There are not sufficient data
available to allow establishing safe processing times for any of these types of
products. It is true that previous
USDA
recommendations had directions for canning mashed winter squash, but
USDA
withdrew those recommendations…

Some of the factors that are critical to the safety of canned pumpkin products
are the viscosity (thickness), the acidity and the water activity. Studies
conducted at the University of Minnesota in the 1970's indicated that there was
too much variation in viscosity among different batches of prepared pumpkin
purees to permit calculation of a single processing recommendation that would
cover the potential variation among products (Zottola
et. al, 1978). Pumpkin and winter squash are also low-acid foods (pH > 4.6)
capable of supporting the growth of Clostridium botulinum bacteria
which can cause the very serious illness, botulism, under the right
storage conditions. If the bacteria are present and survive processing, and the
product has a high enough water activity, they can thrive and produce toxin in
the product.

More recent research with pumpkin butter has been done at the University of
Missouri. Pumpkin butter is mashed or pureed pumpkin that has had large
quantities of sugar added to it, but not always enough to inhibit pathogens.
Sometimes an ingredient such as vinegar or lemon juice is added to the
formulation to increase the acidity (decrease the pH). However, pumpkin butters
produced by home canners and small commercial processors in Missouri have had pH
values as high as 5.4. In fact, the pH values seemed to be extremely variable
between batches made by the same formulation (Holt,
1995).

It is not possible at this point to evaluate a recipe for pumpkin or mashed
squash for canning potential by looking at it. At this point, research seems to
indicate variability of the products is great, and in several ways that raise
safety concerns. It is best to freeze pumpkin butters or mashed squash.”
(emphasis added)

Obviously, pumpkin pie filling is essentially “pureed
pumpkin” and similar to pumpkin butter. This means that neither the cooked
pumpkin puree nor the pumpkin pie filling (puree plus sugar and spices) would be
candidates for safe home canning.

The University of Illinois Extension also says:
“Canning pumpkin butter not a good idea, but try pieces or freezing. “